The present invention relates generally to a patch or access module usable with an insertable patch plug, and more particularly, to an improved switch and contact element in a patch module for electrically connecting or accessing certain leads of a data transmission circuit to a patch cord and electrically disconnecting such leads from their normal electrical connection within the patch module.
Several types of patch or access assemblies presently exist in the prior art. Such assemblies typically include an array of individual patch or access modules disposed in side by side relationship with one another. In these assemblies, each module is adapted for selectively connecting and disconnecting various electrical circuits or leads within the module. In one embodiment, each of the patch modules includes an access to the leads on the computer side of a data transmission circuit and an access to the leads on the modem side of a data transmission circuit. The respective leads from the computer are normally electrically connected with the leads on the modem side, thus providing a through circuit. Patch cords are available for use with the patch modules to electrically connect or patch one set of leads from a particular computer with a second set of leads for a particular modem remote from the particular module in question. Each of these patch cords includes a patch plug on opposite ends for making electrical connection with or accessing the respective computer and modem leads.
To accomplish the above patching function, the patch plug at one end of the patch cord is inserted into an access opening associated with the desired computer data transmission leads and the patch plug at the other end of the patch cord is inserted into the access opening associated with the desired modem data transmission leads. The insertion of the patch plugs into the patch modules accomplishes two things: (1) it causes the normal electrical connection between the computer and modem leads in a particular patch module to be electrically disconnected and (2) it causes electrical connection to be made between the leads being accessed and the corresponding contact elements in the patch plug.
A variety of mechanisms presently exist in the prior art for accomplishing this switching and contact function. In U.S. Pat. No. 4,140,918, the patch plug consists of a generally cylindrical element having a plurality of electrical contacts in which the switching and contact functions are performed by inserting the cylindrical plug into the patch module jack and rotating the plug. In U.S. Pat. No. 4,203,066, the switching function is accomplished by shifting the position of an entire switching board as the patch plug is inserted, with the electrical contact being made as a result of engagement between electrical contacts on the patch plug and contact portions on the surface of the printed circuit board. In another known structure, a plurality of contact springs are utilized with each of the springs associated with one of the leads. As the patch plug is inserted, the spring contact members are electrically disconnected from the leads and electrical contact is made between appropriate contacts in the patch plug and contact portions on the surface of the printed circuit board.
While many of the prior art patch modules and switch-contact mechanisms perform satisfactorily, they do have certain limitations. In many, the switching mechanism is structurally quite complicated, thus leading to high costs in manufacture and fabrication as well as increased chances of malfunction. Also, the contact mechanism in most modules consists of a contact element in the patch making electrical contact with a contact surface on the printed circuit board. This latter structure results in two disadvantages. First, because of the extremely high wear in the area where electrical contact is made, the anticipated useful life of the module is limited. Second, as a result of the continuous wear between the contact elements of the patch plug and the contact surfaces on the printed circuit board, fiber from the printed circuit board is dislodged, thereby resulting in intermittent circuits being formed. This often leads to malfunction of the module.
Accordingly, there is a real need in the art for a patch module having an improved switching and contact mechanism for substantially reducing or eliminating wear between the contact elements associated with the patch plug and the printed circuit board.